1. Field of Invention
The present invention relates to a method of scanning multiple images. More particularly, the present invention relates to a method for shortening multiple-image scanning duration.
2. Description of Related Art
In general, a scanner has a scanning head over a scanning surface. The scanning head is driven by a stepping motor to scan a document. FIG. 1 is a schematic diagram showing the positions of a scanning head 102 driven by a stepper into performing a multiple image scanning operation. As shown in FIG. 1, a multiple of scanning documents A to G is placed over a scanning platform. To carry out an image scanning, the scanning head 102 is driven from an initial position down to the edge line ‘a’ of image A. Image A is scanned until the edge line c of image A is reached. However, during scanning, the scanning head 102 reaches the edge line b of image B first. Consequently, after complete scanning of image A, the scanning head 102 is driven by the stepper back to edge line b before image B can be scanned. By repeating the aforementioned scanning steps, all images on the scanning platform are scanned. The pointed arrows on the left hand side of FIG. 1 indicate the direction of movement of the scanning head 102 driven by the stepper. In other words, the arrows show the stepping movement of the scanning head 102 for a complete scanning of images A˜G.
In a multiple image scanning operation, if a scanning line section is within two or more images, backtracking of the scanning head is required. For example, image A and image B contains a common scanning line section and the scanning head needs to backtrack after scanning image A before scanning image B. Similarly, image B and image C have a common scanning line section and the scanning head needs to backtrack after scanning image B before scanning image C.
During normal scanning, the stepper motor must shuttle back and forth to bring the scanning head 102 into position. Hence, a lot of time is wasted in the conventional method to move the scanning head over overlapping scanning line sections.